Check the lines around where the errors first appear in your logs. Those assets might be the culprit.
Looking at the log I think you should check the following:
- you’re missing the crouch action used in the Ue4ASP_Character. Add the binding and see if an error disappears.
- open the WaveMode asset and check if all is good. Save asset even if it look ok.
I had this same problem a minute ago and fixed it by checking my animations, skeletons and physics assets for errors.
Hope it helps.